For the sequence, the crew constructed a set on a soundstage at England’s Shepperton Studios that looked like the interior of a standard commercial airliner, except that it was supplemented with strategically placed green screens. (Moving Picture Company-London/ Paramount)

Stunt performers hanging from wires and harnesses were filmed in such a way to give the appearance of “zombies and luggage whipping past the camera,” according to visual effects supervisor Scott Farrar. (Paramount)

It’s one of the biggest action set pieces in Paramount’s upcoming pandemic thriller, “World War Z.”

A Belarus Airlines flight attendant opens a rattling closet door only to have a rabid zombie leap toward her. Moments later, a throng of newly turned zombies is sweeping toward the plane’s cockpit, and Brad Pitt’s ex-U.N. investigator Gerry Lane, reasoning that he’s got a better shot of surviving a crash than a zombie attack at 20,000 feet, grabs a grenade belonging to a soldier on the flight and blows apart the cabin.

Gravity rips the zombies from the compromised fuselage into a bright blue sky, and Lane buckles in for dear life as the plane plummets earthward.

“It’s something people haven’t seen before, an outbreak on a plane,” noted “World War Z” director Marc Forster, pausing for just a moment before making the obvious joke. “Only snakes. No zombies. Only snakes on a plane.”

Of course, the Zs are no laughing matter, either in the Max Brooks novel that inspired “World War Z” or in Matthew Michael Carnahan’s screenplay for the film, due out June 21.

The globe-hopping apocalyptic adventure tracks family man Lane as he races around the world trying to hunt down the origin of the disease that appears likely to wipe out mankind, hoping to find some way to bring humanity back from the brink and save his wife and daughters.

For the plane sequence, the crew constructed a set on a soundstage at England’s Shepperton Studios that looked like the interior of a standard commercial airliner, except that it was supplemented with strategically placed green screens to assist the visual effects team in building out the imagery during post-production — and it was rigged to explode.

The sequence was shot over eight days, with two additional days of second-unit filming. Five actors were cast as passengers who became infected; 22 stunt performers bolstered the ranks of the newly turned zombies.

Visual effects supervisor Scott Farrar and his team, which includes animation director Andy Jones (“Avatar”), were tasked with completing 76 shots for the sequence; 38 shots leading to the grenade toss, 38 shots between the toss and the crash landing.

“You’re mixing real zombies with some of the CG zombies,” Forster said. “You want the real zombies in there, especially for Scott and his team to match the CG zombies. Some of them blend so well between humans and CG that you really cannot tell the difference anymore.”

A shot from the plane crash sequence in “World War Z.” (Paramount)

The crew had just one chance to capture the explosion, filmed using six cameras. Afterward, stunt performers hanging from wires and harnesses were filmed being whisked quickly through the open hull to give the appearance of “zombies and luggage whipping past the camera,” Farrar explained.

Pitt too had to endure a fair amount of discomfort, strapped in to his seat as massive fans simulated the wind-tunnel effect on the cabin set.

“The film is intense and real,” Forster said. “It’s the intensity that drives the film.”